The approval came at a time when federal authorities in the United States are implementing a slew of measures to cut down the supply of opioid painkillers amid their continuous abuse, with President Donald Trump in August declaring the opioid epidemic a national emergency.

Osteoarthritis knee pain is a degenerative joint disease that affected more than 14 million Americans in 2015.

(Reporting by Divya Grover and Tamara Mathias in Bengaluru; Editing by Martina D'Couto)